Handmade Ceramic Pottery Coasters with Crushed Glass/Crystal Center

Vintage set of 4 ceramic handmade coasters with a green and clear crushed glass (crystal?) center and cork backing. This set is very well made but there’s no maker’s mark or branding from what I can see. There’s a very small crack on the edge of one coaster, but overall the set is in great condition with no chips or damage. Please refer to photos for item condition and dimensions.